mash: Fix system tray clock 12/24 hour time setting

ash/mus/bridge/wm_shell_mus.cc

Index: ash/mus/bridge/wm_shell_mus.cc
diff --git a/ash/mus/bridge/wm_shell_mus.cc b/ash/mus/bridge/wm_shell_mus.cc
index 60d897cc8f19a2ac93d7907c5b956e5364d71ef5..7c720a87d6ad8e634e968596c9a8b9bbe164bea0 100644
--- a/ash/mus/bridge/wm_shell_mus.cc
+++ b/ash/mus/bridge/wm_shell_mus.cc
@@ -11,7 +11,7 @@
 #include "ash/common/shell_delegate.h"
 #include "ash/common/shell_observer.h"
 #include "ash/common/shell_window_ids.h"
-#include "ash/common/system/tray/default_system_tray_delegate.h"
+#include "ash/common/system/tray/system_tray_delegate.h"
 #include "ash/common/wallpaper/wallpaper_delegate.h"
 #include "ash/common/wm/maximize_mode/maximize_mode_event_handler.h"
 #include "ash/common/wm/maximize_mode/scoped_disable_internal_mouse_and_keyboard.h"
@@ -135,7 +135,8 @@ WmShellMus::WmShellMus(
 
   CreateMruWindowTracker();
 
-  SetSystemTrayDelegate(base::MakeUnique<DefaultSystemTrayDelegate>());
+  SetSystemTrayDelegate(
+      base::WrapUnique(delegate()->CreateSystemTrayDelegate()));
 
   SetKeyboardUI(KeyboardUIMus::Create(window_manager_->connector()));